1. Field of the Invention
The present invention relates to a wireless communicating apparatus for performing a communication by using a spread spectrum communication method.
2. Description of the Related Art
In a communicating system using the spread spectrum communicating method, a communicating method using a frequency hopping method (hereafter, referred to as an FH method) is used in order to improve the effective utilization of a frequency and a security. The FH method performs the spreading by hopping a carrier frequency in accordance with a predetermined rule based on a spread spectrum code sequence. A sending and receiving device in a two-way communicating system using the spread spectrum communicating method by the FH method is constructed, for example, as shown in FIG. 30.
At first, when the sending operation is performed, a signal having a random frequency is outputted by a frequency synthesizer 206 in accordance with the spread spectrum code sequence outputted by a spread spectrum code sequence generator 205. On the other hand, a first modulation signal is inputted to a transmission data input terminal 220. An output frequency of the first modulation signal is determined by an up-converter 203 on the basis of the output of the frequency synthesizer 206. The transmission data which is frequency-converted by the up-converter 203 is amplified by an amplifier 208. Then, it is sent and outputted through a sharing element 210 to an antenna 211.
Next, when the receiving operation is performed, a signal received by the antenna 211 is separated from the transmission signal by the sharing element 210, amplified by an amplifier 209 and inputted to a down-converter 207. Then, it is frequency-converted on the basis of a signal specifying the frequency from the frequency synthesizer 206 by the down-converter 207, and demodulated by a demodulator 212 to thereby become the reception data. This reception data is outputted to a data operation circuit (not shown) and also outputted to a synchronization circuit 204. In the synchronization circuit 204, a phase of a hopping frequency is detected from the reception signal. A synchronization signal is outputted from the synchronization circuit 204 to the spread spectrum code sequence generator 205, which outputs the spread spectrum code sequence on the basis of the inputted synchronization signal. The spread spectrum code sequence outputted by the spread spectrum code sequence generator 205 is sent to the frequency synthesizer 206, which generates the output having the random frequency on the basis of the inputted spread spectrum code sequence.
The down-converter 207 multiplies the reception signal by the output from the frequency synthesizer 206 to thereby inverse-spread to the reception signal (Here, "inverse-spread" means to demodulate a signal modulated (spread) on the basis of a spread spectrum code by using the same spread spectrum code). The reception signal inverse-spread by the down-converter 207 is demodulated by the demodulator 212. The demodulated reception signal is outputted from a reception data output terminal 221.
Accordingly, the two-way communication is performed by the simultaneous operations in the sending and receiving sections as mentioned above.
The random frequency implies that the outputted spread spectrum code is randomly changed each time the synchronization signal is inputted by the spread spectrum code sequence generator 205. The sending and receiving operations are performed under the common utilization of this spread spectrum code sequence (frequency hopping pattern) between one combination of communicating apparatuses.
However, in the conventional apparatuses, the data treated as the transmission data and reception data is only voice data or only non-voice data. Thus, it is impossible to send and receive the mixture of the voice data and the non-voice data.
This is because the uniformly sending and receiving operation is performed independently of the data types although there are the differences between the data characteristics, as described below. Namely, as for the voice data, the data amount which is sent and received at one time is small, and the ability of the real time (the ability of immediate response) is highly required. As for the non-voice data, the data amount which is sent and received at one time is large, and the ability of the real time is not required so much.
Hence, in an apparatus having both functions of a facsimile function and a master and slave phone function, a spread spectrum digital communication, such as the frequency hopping method or the like, can not be performed between the master phone and the slave phone. As a result, it is impossible to improve the security and the frequency utilization efficiency.
Moreover, in the conventional apparatus, in order to perform the simultaneous communications between the master phone and a plurality of slave phones, a hopping frequency data pattern must be changed for each communicating pair, and a plurality of sending and receiving devices must be disposed on the master phone side, which results in the problem of a large-sized apparatus.